The cubic boron nitride has a hardness next to the diamond and excellent thermal conductivity. In addition, the cubic boron nitride has a characteristic that it has low affinity with iron. A cubic boron nitride sintered body comprising cubic boron nitride and a binder phase of a metal(s) or ceramics is applied to a cutting tool or a wear resistant tool, etc.
For example, the conventional cubic boron nitride sintered body comprises 20% by volume or more and 60% by volume or less of cubic boron nitride, and at least Al2O3 and a Zr compound in a binder phase (see Patent Document 1).